Microconstituents in the Aquatic Environment: Regulatory Perspective from Office of Water

Under the United States Clean Water Act (CWA), EPA is required to take a number of actions to protect and restore the ecological integrity of the Nation's water bodies. Specifically under section 304(a) of the CWA, EPA must develop and publish ambient water quality criteria (AWQC), which are levels of individual pollutants, water quality characteristics, or descriptions of conditions of a water body that, if met, should protect the designated use(s) of the water. Examples of designated uses of a water body include swimming, drinking water, fishing, fish spawning, and navigation. States and authorized tribes establish designated uses for their water bodies. AWQC are recommended guidance that states and tribes may use as part of their water quality standards to protect water bodies for their designated use from chemical pollutants.